Diversity antenna



Jan. 9; 1940. w, M r 2,186,422

nivERsITY ANTENNA ARR! V/NG SIGNAL Filed June 8, 193a ARR/V/IVG SIGNAL70 ANTENNA INVENTOR.

I I. Mam/5W5 B Y MW ATTORNEY.

PatentedJana-iwc I s 2,186,422

UN!Tel)- [STATE-S PATENT o FF C- i"j, I

3 DIVERSITY ANTENNA I Walter 1. Matthews, Riverheacl, N. Y.,'assignor'to Radio Corporation of America, a corporation of Delaware l 3Application June 8, 1938, Serial No. 212,410, U

, v 12Claims. (Cl. 250-11) I o This invention relates to radio receivinganare separatedand separatelytransmitted; to they tennas and, morespecifically, to a single antenna receiving apparatus. structure for thedirective reception of radio Referring, now, fora. morecompleted-isclosure' waves polarized in horizontal and vertical planes.of my invention, to the following detailed de- It hasheretofore been thepractice, in order to scription, which is accompanied by drawing, in 5mitigate fading of short wave-signals,'to receive which v I i eitherhorizontally or vertically polarized signals Figures 1 and 2 illustratediagrammatically the on two or more geographically spaced antennas;separate components of my antenna whileFig'ure The resultant output fromeach antenna is then 3 illustrates an embodiment of my inventionandcombined at the receiving station so that even Figure 4 illustratesaxcoupling means for coupling though the signal received fromone of theantransmission linesto the antenna. v tennas is-at a very low level dueto-a fading of the ,Referring'to Figure 1 it will be seen'that'theresignal, the signal from the other antenna may is a pair of linearconductors .l and 2 to which still be of usable strength. I Thisprinciple has are coupled transverse pick-up wires 6. The been calledthe diversity principle and is orditwoconductors l-and ZQare parallel toone annarily applicable to antennas of like kind 'sepaother and extendfromtransmission,linei TL, in rated in space. the direction of. thedesired reception. The pick- For successful operation of this system theup wires Bare. arranged in a horizontal plane antennas must be spacedjanumber of'waveandat right angles to the conductors .l and 2.lengths'apart and, hence, requires the use of con- The pick-up wires 6may be either directlyconr- ".20 siderable area of ground. nectedto'wires l and 2 or may be coupled there- Tests have shown that a markeddiversity efto through limiting impedanceswhich may take fectexists'between vertical and horizontal arrays the form of smallseriescondensers, or .theymay located atapproximately the samegeographical becoupled thereto in. any other known .f'ashion.

location; I

An object, therefore, of the present invention best \to horizontallypolarized waves. An anis the application of this polarization diversitytenna of this general'type is more completely deefiect to'a' singleantenna structure. scribed in a patentto H. O. Petersen, No. 1321,5102,

Another-object of my invention is to provide grantedSeptember 1, 1931.

Theantenna, as. shown in this figure, responds .25

a'single antenna structurewhich is selectively The antenna, shown; inFigure 2 consistsv of :30

responsive to bothhorizor'itally and vertically conductors I land 32connected. in series and polarized radio waves. arrangedin a commonvertical plane. They As a further object, the presentinvention-inare'arranged in such a manner as to describe a volves thesimultaneous transmission of both vertical half diamondwith respect tothe earth. horizontally and vertically polarized, waves. In determiningthe physical dimensions of'such 35 Still another-object of the presentinvention is an array, wires l2 and 32 should, preferably, to accomplishsimultaneoustransmission and reeachbe a number of wavelengths long andeach ception on the same frequency band, using a of the wires shouldbe'a half wavelength longer single-antenna structure and withoutmutual'inthantheir projected distance A on the ground. 40 terference. fThis type of antenna responds best to vertically 40 My present inventionrelates to a single array polarized waves. which responds'to bothvertical/and horizontal My invention, as shown in Figure 3, involvespolarized waves and, briefly, consists of a pair'of the combination of avertical array of Figure 2- Wiresarranged in a vertical half diamond andexwith the horizontal array of Figure '1. The

tending in the direction of desired reception. To single wire normallyused as a vertical half dia- 45 each of thewires of the-half diamond isattached "mond is replaced bythe two sets of wires I3, 33 a plurality ofhorizontal half wave antennae arand. 23, 43. These wires are relativelyclosely ranged transversely to the half diamond. The spaced so as toproduce a transmission line for vertical half diamond constructionenables the the horizontally polarized waves picked up by antenna toreceive vertically polarized signals pick-up wires ii. The dipolepick-up wires 6,,as 50 while the horizontal dipoles attached theretoredescribed with r sp ct to F gur 1, are connec ed spond' to thehorizontally polarized wave. By C O e t ansmission line and (1 51 5 inmeans of a suitable. coupling arrangement beplanes parallel to theearth.. These doublets retween the antenna and the. transmission line,'spond primarily to the horizontally polarized the two components of thereceived signal wave I waves. :At the end of the array remotefrom thedirection of the arriving signal a transducer for separating thevertical and horizontal components for transfer to the transmission lineleading to the radio receivers is provided. This transducer is showndiagrammatically in Figure 4.

The transducer comprises a center tapped coil I and a transformer I6.The two ends of coil I5 are connected to the transmission wires I3 and23. From the center tap of coil I5 to ground is connected primary I! oftransformer I6. The ends of coil I5 are connected to transmission lineTLH which carries the horizontally polarized waves to the receiver whilethe secondary I8 of the transformer I 6 is connected to the transmissionline TLV for a vertical component of the received signal waves. It willbe apparent that for horizontally polarized signal waves the endterminals of coil I5 will experience voltages of opposite polarity thustransferring signal energy to the transmission line TLH, while nodiflference of potential will exist between the center tap and groundand, therefore, none of the energy due to the horizontally polarizedsignal waves will appear across the secondary I 8 of the trans' former.For vertically polarized waves the end terminals of coil I5 receivevoltages of like polarity thus resulting in no energy transferring totransmission line 'I'LI-I. These like voltages, however, give rise to apotential difference across coil I! and thus result in a transfer ofen.-

ergy to the transmission line TLV. If desired. in

order to prevent reflections in the transmission line or to increasediscrimination against signals arriving to the array from the direct onapposite to that shown by the arrow in the figures, terminatingimpedances may be providedacross the ends of the conductors 33 and 43remote from the transmission line. Also. it should be apparent that myinvention is equally adapted to the use of transmission, it then beingmerely necessary to connect the proper transmission apparatus totransmission lines TLI-I and TLV.

Furthermore, it is also possible to utilize one transmission line totake received signals of one polarization to a receiver, while the othertransmission line can be used to take energy from a transmitter to theantenna to radiate waves of the other polarization at the same time. thereceivingand transmission operations occurring without mutualinterference due to the lack of .to at intervals along said conductors,said conductors being arranged in a vertical half diamond configurationwith respect to the earth.

'2. A directive antenna comprising a pair .of

relatively closely spaced conductors and a plu-, rality of transversehorizontal pick-up wires coupled thereto at intervals along saidconductors, said conductors being arranged in a vertical half diamondconfiguration with respect to the earth.

3. A directive antenna comprising a pair of relatively closely spacedconductors and a plurality of transverse pick-up wires coupled theretoat intervals along said conductors, said conduct ors being arranged in avertical half diamond intervals along said conductors, signal responsivemeans connected to' one end of said conductors, said conductors beingarranged in a vertical half diamond configuration with respect to theearth with the end of said conductors remote from said means directedtoward the source of said signals.

5. A directive antenna comprising a pair of relatively closely spacedconductors, the ends of said conductors being supported comparativelynear the earth and their midpoints substantially elevated thereabove, aplurality of transverse pick-up wires coupled with said conductors atspaced intervals along said conductorsand signal responsive meansconnected to one end of said conductors.

6. A directive antenna comprising a pair of relatively closely spacedconductors, the ends of said conductors being supported comparativelynear the earth and their midpoints substantially elevated thereabove, aplurality of transverse horizontal pick-up wires coupled to saidconductors at spaced intervals along said conductors and signalresponsive means connected to one end of said conductors.

7. In combination, a source of radio signals, a directive antennacomprising a pair of relatively closely spaced conductors, the ends ofsaid conductors being supported comparatively near the earth and theirmidpoints substantially elevated thereabove, a plurality of transversepickup wires coupled to said conductors at spaced points along saidconductors, one end of said conductors being directed toward said sourceand signal responsive means connected to the other end of saidconductors.

8. In combination, a source of radio signals, a directive antennacomprising a pair of relatively closely spaced conductors, saidconductors being arranged in a vertical half diamond configuration withrespect to the earth, a plurality of transverse horizontal pick-up wirescoupled thereto along the length of said conductors, one end, ofsaidconductors being directed toward said source of radio signal's'andsignal responsive means connecte'd to the other end of said conductors.Y i

9. A directive antenna comprising a pair of relatively closelyspacedconductors, the ends of said conductors being supportedcomparatively near the earth and their midpoints substantially elevatedthereabove, a plurality of transverse horizontal pick-up wires coupledthereto at spaced intervals along the length of said conductors, acenter tapped coil connected to one end of said con-ductors,transmission line also connected thereto, a transformer having its primary connected from said center tap to ground and itssecondaryfconnected to a second transmission line. I

10'. A directive antenna comprising a pair of relatively closely spacedconductors, the ends of said conductors being supported comparatively,near the earth and their midpoints substantially elevated .thereabove,a plurality of transverse horizontal pick-up wires coupled thereto atspaced intervals along the length of said conmary connected from saidcenter tap to ground and its secondary connected to a secondtransmission line and signal responsive means connected to each of saidtransmission lines.

11. In combination, a source of radio signals,

a directive receiving antenna comprising a pair of relatively closelyspaced conductors, said conductors being arranged in a vertical halfdiamond configuration with respect to the earth, one end of saidconductors being directed toward said source, a plurality of transversehorizontal pickup Wires coupled to said conductors, a center tapped coilconnected to the end of said conductors remote from said source, atransmission line also connected thereto, a transformer having itsprimary connected from said center tap to ground and its secondaryconnected to; a second transmission line.

12. In combination, a source of radio signals, a directive receivingantenna comprising a pair of relatively closely spaced conductors, saidconductors being arranged in a vertical half diamond configuration withrespect to'the earth, one end of said conductors being directed towardsaid source, a plurality of transverse horizontal pickup wires coupledto said. conductors, a center tapped coil connected to the end ofsaidconductors remote from said source, a transmission line alsoconnected thereto, a transformer having its primary connected from saidcenter tap to ground and its secondary connected to a secondtransmission line, and signal responsive

